1. Field of Invention
This invention relates to packaging of a plurality of disks. More particularly, the invention relates to a fiber disk package and retainer and packaging method which offer improved shelf-life, stockability and curl prevention.
2. Related Art
One common form of abrasive article includes discs which are typically used for grinding. The disk is usually assembled with a rigid rotatably mountable support pad. These types of abrasive articles are typically made of paper, polymeric materials, cloth, nonwoven materials, vulcanized fiber, or combinations of these materials to perform a desired sanding operation.
While the vulcanized fiber disks are highly desired, these disks are very susceptible to age unacceptably rapidly. Vulcanized fiber backings are desirable because they are heat resistant and strong. Vulcanized fiber is used in grinding operations, such as weld grinding, contour grinding, and edge grinding. The main disadvantage of the vulcanized fiber disk is that it is relatively expensive, hygroscopic and sensitive to humidity. The disks are therefore difficult to maintain flat in humid conditions and under conditions of high and low humidity, vulcanized fiber will be affected by either expansion or shrinkage, due, respectively, to water absorption or loss. Consequently, the vulcanized disks will warp or curl with the abrasive coated side convex outward. Once curled, the disk does not lay flat against the support pad and when trying to flatten the disk they are subject to breaking as they are typically very brittle. This essentially renders the coated abrasive disc inoperable. This warping often occurs while on the shelf in the store or once opened from the package wherein one or more unused disks may be rendered to waste. This is a significant problem.
One thought at solving the problem was to add a number of holes in the disk to take out some of the stresses that build up in a sanding disk. This was thought lessen the curled state and render it more susceptible to straighten the disk. This however has produced less than a desirable result and has not significantly solved the curling issue. Another attempt was to provide a plastic clam shell package about the disks in an effort to prevent curling. However, this also has met with less than acceptable results.
Accordingly, there is a need to prevent curl in abrasive material. There is a need to provide a way to package and maintain abrasive materials in a way to prevent or minimize curl. The instant invention solves these needs.